Self-centered inlay and core layer for information carrying card, process and resulting products

ABSTRACT

The disclosure provides a method for forming a core layer for at least one information carrying card, and resulting products. The method includes forming an inlay layout, and dispensing a crosslinkable polymer composition over the inlay layout and contacting the inlay layer so as to form the core layer of the information carrying card. The inlay layout includes at least one inlay layer coupled with a first thermoplastic layer. The first thermoplastic layer comprises a thermoplastic material, and defines at least one hole therein. The at least one inlay layer is disposed at least partially inside a respective hole.

RELATED APPLICATIONS

The disclosure relates to the materials disclosed in the followingapplications and the applications based on the following applications,which applications are incorporated by reference in their entirety as ifset forth fully herein:

(1) U.S. patent application Ser. No. 13/801,630, filed Mar. 13, 2013;

(2) U.S. patent application Ser. No. 13/801,677, filed Mar. 13, 2013;

(3) International Application No. PCT/US2014/021548, filed Mar. 7, 2014;and

(4) International Application No. PCT/US2014/50987, filed Aug. 14, 2014.

FIELD OF THE INVENTION

The disclosure relates to information carrying cards such as smartcards. More particularly, the disclosed subject matter relates to amethod of making an core layer for an information carrying card, and theresulting core layer and the information carrying cards.

BACKGROUND OF THE INVENTION

Information carrying cards provide identification, authentication, datastorage and application processing. Such cards or parts include keycards, identification cards, telephone cards, credit cards, bankcards,tags, bar code strips, other smart cards and the like. Counterfeitingand information fraud associated with traditional plastic cards causestens of billions of dollars in the losses each year. As a response,information carrying cards are getting “smarter” to enhance security.Smart card technologies provide solutions to prevent fraud and decreaseresulting losses.

Information carrying cards often include an integrated circuit (IC)embedded in a thermoplastic material, such as polyvinyl chloride (PVC).Information has been input and stored in the integrated circuit before atransaction. In use, information carrying cards work in either a“contact” or “contactless” mode. In contact mode, an electroniccomponent on the card is caused to directly contact a card reader orother information receiving device to establish an electromagneticcoupling. In contactless mode, the electromagnetic coupling between thecard and the card reading device is established through electromagneticaction at a distance, without the need for physical contact. The processof inputting information into the IC of the information carrying cardalso works in either of these two modes.

When information carrying cards become “smarter,” the amount ofinformation stored in each card often increases, and the complexity ofthe embedded IC's also increases. The cards also need to withstandflexing to protect sensitive electronic components from damage as wellas offer good durability during use. A relatively easy and full-scalecommercial process having improved productivity at low cost is alsodesired.

SUMMARY OF THE INVENTION

The invention provides a core layer for an information carrying cardcomprising a self-centering inlay layout or design, the process ofmaking the core layer, and the resulting products. The core layer alsocomprises a cross-linked polymer composition, and the self-centeringinlay layout is suitable for fabrication of a core layer through athermal lamination process.

In some embodiments, a method for forming a core layer for at least oneinformation carrying card comprises the steps of forming an inlay layoutcomprising at least one inlay layer coupled with a first thermoplasticlayer, dispensing a crosslinkable polymer composition over the inlaylayout and contacting the inlay layer so as to form the core layer ofthe information carrying card. The first thermoplastic layer comprises athermoplastic material, and defines at least one hole therein (ortherethrough). The at least one inlay layer is disposed at leastpartially inside a respective hole. The step of forming the inlay layoutmay comprise the steps of providing the first thermoplastic layerdefining the at least one hole therein, disposing the at least one inlaylayer at least partially or fully inside a respective hole, and couplingthe at least one inlay layer and the first thermoplastic layer (e.g.,using an adhesive tape, an adhesive, a solder, or any other suitablechemical or physical technique). In some embodiments, the at least oneinlay layer is flexibly coupled to the first thermoplastic layer so asto form a cantilevered structure adjacent to or within a respective holeso as to be suitable for self-centering relative to the edges of thehole, particularly in the presences of a crosslinkable polymercomposition during a processing step, for example, during a step ofvacuuming and/or heating. Such a process may be performed in a mold.

The method may further comprise one of the following steps: disposingthe first thermoplastic layer over a first release film, applying vacuumto the crosslinkable polymer composition, and disposing a secondthermoplastic layer or a second release film above the inlay layoutafter dispensing the crosslinkable polymer composition. The first orsecond thermoplastic layer may comprise a thermoplastic materialselected from the group consisting of polyvinyl chloride, copolymer ofvinyl chloride, polyolefin, polycarbonate, polyester, polyamide, andacrylonitrile butadiene styrene copolymer (ABS). The crosslinkablepolymer composition comprises: a curable precursor, which may beselected from the group consisting of acrylate, methacrylate, urethaneacrylate, silicone acrylate, epoxy acrylate, methacrylate, silicone,urethane and epoxy. The crosslinkable polymer composition is a liquid ora paste, and curable under heat or radiation, or both. The method mayfurther comprise a step of curing the crosslinkable polymer compositionto form a crosslinked polymer composition. The curing step may beperformed under a pressure using radiation or at a raised temperature,or both radiation and heat. Such a pressure may be equal to or less than2 MPa, and the raised temperature might be equal to or less than 150° C.

In some embodiments, the at least one inlay layer comprises at least oneelectronic component. The at least one electronic component is partiallyor fully located within the respective hole in the first thermoplasticlayer. The at least one electronic component in the inlay layer maycomprise at least one integrated circuit, at least one light emittingdiode (LED) component, or a battery. The inlay layout or the core layermay comprise at least one of a metal sheet (such as stainless steel), aceramic sheet, a wooden sheet, and carbon fiber based sheet. In someembodiments, the first thermoplastic layer defines a plurality of holestherein (or therethrough), the inlay layout comprises a plurality ofinlay layers flexably coupled to the first thermoplastic layer, eachinlay layer being located within a respective one of the plurality ofholes so as to form a cantilevered structure adjacent to a respectivehole and be suitable for self-centering relative to the edges of thehole, particularly in the presences of a crosslinkable polymercomposition during a processing step. The resulting core layer is formaking a plurality of information carrying cards simultaneously.

In another aspect, a method for fabricating at least one informationcarrying card is provided that includes forming a core layer asdescribed above. Such a method for making information carrying card maycomprise laminating a printable thermoplastic film on one side of thecore layer. A printable thermoplastic film may be laminated on each sideof the core layer. Such a method may further comprise laminating atransparent thermoplastic film on the printable thermoplastic film onone side of the core layer. A transparent thermoplastic film may belaminated on the printable thermoplastic film on each side of the corelayer.

In another aspect, a resulting product is provided that includes a corelayer and a final information carrying card. In some embodiments, a corelayer for at least one information carrying card comprises at least onethermoplastic layer defining at least one hole therein (ortherethrough), an inlay layout comprising at least one inlay layercoupled (e.g., flexibly coupled) to the first thermoplastic layer, and acrosslinked polymer composition disposed over the inlay layout andcontacting the inlay layer. In some embodiments, each inlay layer is atleast: (i) partially disposed within a respective hole, and/or (ii)partially movable relative to the edges of the first thermoplastic layerthat define the hole. The first thermoplastic layer may comprise athermoplastic material selected from the group consisting of polyvinylchloride, copolymer of vinyl chloride, polyolefin, polycarbonate,polyester, polyamide, and acrylonitrile butadiene styrene copolymer(ABS). The at least one inlay layer may be flexibly coupled to the firstthermoplastic layer, each inlay layer being located so as to form acantilevered structure adjacent to or within a respective hole and beingself-centered relative to the edges of the first thermoplastic layerthat defines the hole. The at least one inlay layer comprises at leastone electronic component, wherein the at least one electronic componentis partially or fully disposed within the edges of the firstthermoplastic layer that define the hole. The at least one electroniccomponent of the inlay layer may comprise at least one integratedcircuit, at least one light emitting diode (LED) component,communications circuitry, or a battery. The inlay layout or the corelayer may comprise at least one of a metal sheet (such as stainlesssteel), a ceramic sheet, a wooden sheet, and carbon fiber based sheet.The crosslinked polymer composition comprises a base unit selected fromthe group consisting of acrylate, methacrylate, urethane acrylate, esteracrylate, silicone acrylate, epoxy acrylate, silicone, urethane andepoxy. The base unit comprises urethane acrylate or epoxy in someembodiments. In some embodiments, the first thermoplastic layer definesa plurality of holes therein, the inlay layout comprises a plurality ofinlay layers coupled with the first thermoplastic layer, each inlaylayer is disposed inside a respective hole of the plurality of holes,and the core layer is configured to be used for making a plurality ofinformation carrying cards.

In some embodiments, an information carrying card comprises the corelayer as described above. The information carrying card comprises atleast one printable thermoplastic film laminated onto the surface of theinlay layout and the crosslinked polymer composition. The informationcarrying card may further comprise at least one transparent filmlaminated onto the surface of the printable thermoplastic film.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is best understood from the following detaileddescription when read in conjunction with the accompanying drawings. Itis emphasized that, according to common practice, the various featuresof the drawings are not necessarily to scale. In some instances, thedimensions of the various features are arbitrarily expanded or reducedfor clarity. Like numerals denote like features throughout thespecification and the figures.

FIG. 1 illustrates an elevation view of an exemplary self-centeringinlay layout comprising a plurality of inlay layers coupled with a firstthermoplastic layer, in accordance with some embodiments.

FIG. 2 illustrates a partial plan view of the self-centering inlaylayout of FIG. 1.

FIG. 3 illustrates a magnified view of the self-centering inlay layoutof FIG. 2 showing an inlay layer coupled with the first thermoplasticlayer.

FIG. 4 is an exploded view illustrating the method for coupling oneinlay layer with a first thermoplastic layer, in accordance with someembodiments.

FIG. 5 is a partial exploded view of FIG. 4.

FIG. 6 is a partial elevation view illustrating an inlay layer coupledonto the first thermoplastic layer.

FIG. 7 illustrates a sectional view of the inlay layer and the firstthermoplastic layer of FIG. 6.

FIG. 8-10 illustrate sectional views of an exemplary core layer having aself-centered inlay layout during a process of fabrication includingapplying a crosslinkable polymer composition in accordance with someembodiments.

FIG. 11 is a partial plan view of the exemplary core layer of FIGS.8-10.

FIG. 12 illustrates a plan view of an exemplary core layer for oneinformation carrying card in accordance with some embodiments.

FIG. 13 is a flow chart diagram illustrating an exemplary process offorming a core layer of an information carrying card, wherein the corelayer comprises a plurality of inlay layers, in accordance with someembodiments.

FIG. 14 is a flow chart diagram illustrating an exemplary process forcoupling a plurality of inlay layers onto a first thermoplastic layer,in accordance with some embodiments.

FIGS. 15-18 illustrate partial cross section views of layered structuresat different steps in the exemplary process of FIG. 13.

FIG. 19 is an plan view illustrating a mold plate having an outside shimand an inside shim in accordance with some embodiments.

FIG. 20 illustrates a cross section view of an exemplary mold used forforming a core layer for an information carrying card in someembodiments.

FIGS. 21-26 illustrate cross section views of the layer structure atdifferent steps of an exemplary process of making an exemplaryinformation carrying card, in accordance with some embodiments.

FIG. 21 is a cross section view of a transparent film.

FIG. 22 is a cross section view of a printable film disposed over thetransparent film of FIG. 19.

FIG. 23 is a cross section view of the layer structure after anexemplary core layer is disposed over the two films of FIG. 20.

FIG. 24 is a cross section view of the resulting layer structure after asecond printable film is disposed over the layer structure of FIG. 21.

FIG. 25 is a cross section view of the resulting layer structure after asecond transparent film is disposed over the layer structure of FIG. 22.

FIG. 26 is a flow chart diagram illustrating an exemplary process ofmaking an exemplary information carrying card.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

This description of the exemplary embodiments is intended to be read inconnection with the accompanying drawings, which are to be consideredpart of the entire written description. In the description, relativeterms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,”“below,” “up,” “down,” “top” and “bottom” as well as derivative thereof(e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should beconstrued to refer to the orientation as then described or as shown inthe drawing under discussion. These relative terms are for convenienceof description and do not require that any apparatus to be constructedor operated in a particular orientation. Terms concerning attachments,coupling and the like, such as “connected” and “interconnected,” referto a relationship wherein structures are secured or attached to oneanother either directly or indirectly through intervening structures, aswell as both movable or rigid attachments or relationships, unlessexpressly described otherwise.

For brevity, unless expressly stated otherwise, references to“information carrying card” or “smart card” made throughout thisdescription are intended to encompass at least key cards, identificationcards, telephone cards, credit cards, bankcard, power cards, tags, barcode strips, any part comprising an integrated circuit (IC), and thelike. “Information carrying card” or “smart card” also includes a widevariety of shapes, which include but are not limited to rectangularsheets, circular sheets, strips, rods and rings. “Information carryingcard” or “smart card” also includes any information carrying parts ofboth “contact” and “contactless” modes. “Information carrying card” or“smart card” also encompasses any information carrying cards with orwithout an on-board power supply. An information carrying cardcomprising a power supply is also referred as a “power card.”

The invention provides a core layer for an information carrying cardcomprising a self-centering inlay layout or design, the process ofmaking the core layer, and the resulting products. The core layer alsocomprises a cross-linked polymer composition, and the self-centeredinlay layout is suitable for fabrication of a core layer through athermal lamination process.

1. Inlay Layout

Referring to FIGS. 1-12, the present disclosure provides an exemplaryinlay layout 2 in accordance with some embodiments.

Referring to FIGS. 1-5, in some embodiments, an exemplary inlay layout 2comprises a first thermoplastic layer 6, and at least one inlay layer 8flexibly coupled to the first thermoplastic layer 6. The at least oneinlay layer 8 may be coupled to the first thermoplastic layer 6, forexample, using a link 4 such as adhesive tape, an adhesive, a solder, orany other suitable chemical or physical means. The coupling may also beperformed using an instant adhesive. The composition of the adhesive oradhesive on an adhesive tape may be any suitable material, including butnot limited to epoxy, polyurethane, and acrylate. In some embodiments,the first thermoplastic layer 6 comprises a thermoplastic material, thathas been cut or otherwise formed so as to yield a plurality of internaledges (e.g., 6 a, 6 b, 6 c, 6 d, 6 e and other internal edges) thattogether define at least one hole 7. In many embodiments of theinvention, a plurality of internal edges (e.g., 6 a to 6 b) define anarray of holes 7 within first thermoplastic layer 6. A first portion 8 aof the at least one inlay layer 8 is positioned at least partially orfully within a respective hole 7 with a second portion 8 b securelycoupled to a support edge 6 a of first thermoplastic layer 6 so thatinlay layer 8 is cantilevered to first thermoplastic layer 6. In thisway each, cantilevered inlay 8 is free to move, relative to edges 6 band through a respective hole 7. This structural arrangement allowscantilevered inlay 8 to be self-centering in the presence ofcrosslinkable polymer composition 16 during a processing step asdescribed herein, for example, during a step of vacuuming and/orheating. Advantageously, during processing steps that entail theapplication of a vacuum or heat, cantilevered inlay 8 is able tooscillate about support edge 6 a and between positions that may be aboveinternal edges 6 b, 6 c, 6 d and 6 e of first thermoplastic layer 6 orbelow internal edges 6 b, 6 c, 6 d and 6 e thus allowing gases and thelike that are volatilized by the lowered pressure or increasedtemperature, to pass freely across holes 7 without being trapped orsuffering undue impedance from cantilevered inlay 8.

Referring to FIGS. 13-14 and 4-6, the step of forming inlay layout 2(step 22 of FIG. 13) may comprise the steps 32, 34, and 36. At step 32,the first thermoplastic layer 6 defining the at least one hole 7 therein(or therethrough) is provided. At step 34, the at least one inlay layer8 is at least partially or fully disposed within a respective hole 7. Atstep 36, the at least one inlay layer 8 is coupled with the firstthermoplastic layer 6 (e.g., using a link 4 such as a tape havingadhesive). An instant adhesive, a solder, any other suitable material ormethod, or the like can be used to couple inlay layer 8 with the firstthermoplastic layer 6. Examples of an instant adhesive include but arenot limited to cyanoacrylate.

First thermoplastic layer 6 can be molded or laminated from one or morelayers of thermoplastic films. Examples of materials that are suitablefor use in forming first thermoplastic layer 6 include polyvinylchloride (PVC), a copolymer of vinyl chloride, polyolefin,polycarbonate, polyester, polyamide, acrylonitrile butadiene styrenecopolymer (ABS), and the like. The first thermoplastic layer 6 may be aPVC, or a copolymer of vinyl chloride and another monomer such as vinylether, vinyl ester or vinyl acetate, or a compound or blend of PVC and avinyl chloride polymer. Examples of PVC films suitable for use with theinvention are available from suppliers such as Klockner Pentaplast ofAmerica, Inc. of Gordonsville, Va.; and Shijiazhuang Eurochem Co. Ltd ofChina. Examples of such copolymer resins are available from Dow ChemicalCompany under trade name of UCAR®, and from BASF of Ludwigshafen,Germany under trade name of Laroflex®. UCAR® is a copolymer of vinylchloride and vinyl acetate. The grades include YYNS-3, VYHE1 and VYHD.Laroflex® is a copolymer of vinyl chloride and vinyl isobutyl ether. Thegrades include MP25, MP 35, MP45 and MP60. All of these polymer resinsmay be supplied as fine powder. A powder of these copolymers can beadded to modify PVC resins for films. First thermoplastic layer 6 havingat least one hole can be formed by die-cutting one or more thermoplasticfilm. Examples of a polyolefin based film may be TESLIN® product,available from PPG Industries.

Referring to FIGS. 4-5, inlay layer 8 is disposed within a respectivehole 7 of the first thermoplastic layer 6. The inlay layer 8 ispartially or fully disposed within hole 7. Inlay layer 8 comprises atleast one active or passive electronic component 10 embedded or surfacemounted on a supporting film 12. Inlay layer 8 may comprise a printedcircuit board (PCB). Electronic component 10 may be embedded or surfacemounted on the PCB supporting material. Examples of supporting film 12include but are not limited to polyimide, polyester such as PET, glassfilled epoxy sheet such as FR-4. A printed circuit board (PCB) havingall the components are abbreviated as PCBa. For brevity, the referencesto PCB in this disclosure will be understood to encompass any PCBsincluding PCBa. Examples of electronic component 10 inside inlay layer 8include but are not limited to active or passive electronic components,e.g., an integrated circuit (IC), a battery (10-1) for a “power card,” apushing button (10-2), an antenna, and a functional component such aslight emitting diodes (LED). Electronic components are interconnectedvia wires or traces 14. Supporting film 12 may be a polymer baseddielectric material. Inlay layer 8 may have any dimension relative tothe size of a hole in first thermoplastic layer 6. Inlay layer 8 may bepartially or fully disposed in such a hole. In some embodiments, thesize of the hole on first thermoplastic layer 6 is larger than the sizeof inlay layer 8. Inlay layer 8 may be fully disposed in the hole. Insome embodiments, the size of the hole 7 in first thermoplastic layer 6is substantially the same as or slightly larger than the size of inlaylayer 6 of PCB. The shape of the hole often matches with the shape ofinlay layer 8. In some embodiments, the size of the at least one hole onfirst thermoplastic layer 6 is less than the size of inlay layer 8. Thesize of the at least one hole is substantially the same as or slightlylarger than a portion of inlay layer 8 of the PCB. For example, theshape and size of one hole may match with one electronic component 10.Examples of electronic component 10 include but are not limited to abattery or an active or passive electronic component, e.g., anintegrated circuit (IC) in inlay layer 8. In one preferred embodiment,the size of the inlay layer is slightly smaller than that of therespective hole 7.

In some embodiments, inlay layer 8 may comprise a piece or a sheet ofmetal, ceramic, metal containing material, ceramic containing material,wood, and carbon fiber based material, plastic or the like. Examples ofsuitable materials for this piece or sheet include but are not limitedto platinum, copper, tungsten, metallized power containing materials,alumina, silica, and ceramic powder containing materials. This piece orsheet may be in a certain color or weight, having certain visual orother sensational characteristics.

Referring to FIGS. 4-6, at step 36, the at least one inlay layer 8 iscoupled to the first thermoplastic layer 6 (e.g., using an adhesive tape4). Examples of a suitable tape 4 include but not limited to polyimide,polyvinyl chloride (PVC), a copolymer of vinyl chloride, polyolefin,polycarbonate, polyester, polyamide, acrylonitrile butadiene styrenecopolymer (ABS), and the like. An instant adhesive, a solder, any othersuitable material or method, or the like can be used to couple inlaylayer 8 with the first thermoplastic layer 6. Examples of an instantadhesive include but are not limited to cyanoacrylate. Any othersuitable chemical or mechanical means can be also used to couple the atleast one inlay layer 8 to the first thermoplastic layer 6. In someembodiments, as described in FIGS. 3-6, only a portion 8 a of inlaylayer 8 is coupled to one internal edge 6 a of the first thermoplasticlayer 6.

Referring to FIGS. 7-12, inlay layer 8 is coupled with the firstthermoplastic layer 6 so as to form a cantilevered structure inside arespective hole 7 inside the first thermoplastic layer 6, and isconfigured to be self-centering in the crosslinkable polymer composition16 during a processing step as described herein, for example, during astep of vacuuming and/or heating. Referring to FIG. 7, the inlay layer 8is coupled with the first thermoplastic layer 6 on one end 8 a, theother end or portion 8 b can vibrate or move freely. In this way each,cantilevered inlay 8 is free to move, relative to edges 6 b and througha respective hole 7. Referring to FIG. 8, when a crosslinkablecomposition 16 in the form of liquid or paste is applied over inlaylayer 8, with or without using two mold plates 15 and 17, inlay layer 8moves during the degasing of the composition 16, or during the heatingstep for curing the composition 16, or both. Thus, inlay layer 8automatically adjusts its position. This inlay layout 2 provides anefficient way to let the air bubbles in composition 16 out and alsolevel itself to form a flat surface of core layer to be made. Referringto FIG. 12, one area with one inlay layer 8 in a respective hole 7provides a core layer for one information card. Referring back to FIGS.1-3, the inlay layout 2 can provide a core layer for a plurality ofinformation carrying cards.

2. Core Layer for Information Carrying Card

Referring to FIGS. 13-19, an exemplary method 20 forming a core layerfor at least one information carrying card in FIG. 13 is described inview of the structures illustrated in FIGS. 15-17. A resulting exemplarycore layer 80 is illustrated in FIG. 20. For the purpose of illustrationonly, FIGS. 15-17 and 20 only are cross section views of a portion ofthe core layer having one inlay layer for one information carrying card.FIGS. 15-17 and 20 can be interpreted as a core layer having a pluralityof inlay layers for a plurality of information carrying cards.

Referring to FIG. 13, in some embodiments, a method for forming a corelayer for at least one information carrying card comprises one or moreof the steps 22, 24, 25 and 26. At step 22 as described above, an inlaylayout 2 comprising at least one inlay layer 8 coupled with a firstthermoplastic layer 6 is formed. Referring to FIG. 14, step 22 (such asan exemplary method 30 for forming an inlay layout 2) can comprise oneof more of steps 32, 34, and 36. Referring to FIG. 14, method 30 mayalso comprise step 38, disposing the first thermoplastic layer 6 over arelease film 42 (a first release film). FIG. 15 illustrates thestructure after an inlay layout 2 is disposed over the first releasefilm 42. The first release film 42 (or any other release film used inother steps in the present disclosure) may be a sheet ofpolytetrafluoroethylene under the trade name Teflon®, any otherfluoropolymer, silicone, a fluoropolymer or silicone coated films. Insome embodiments, a breathable release film is preferred. Examples of abreathable release film is a silicone coated paper. For example, releasefilm 42 may take the form of a silicone coated, unbleached parchmentbaking paper, available from Regency Wraps company under the trade nameof “If you care.” The one release film is shown for the purpose ofillustration only. None or two release films may be used in someembodiments.

Referring back to FIG. 13, at step 24, a crosslinkable polymercomposition 16 is dispensed over the inlay layout 2 and contacting theinlay layer 2 so as to form the core layer 80 of the informationcarrying card 100.

Referring to FIG. 16, the resulting layer is shown, after across-linkable polymer composition 16 is dispensed over the firstthermoplastic layer 6, and the inlay layer 8 (i.e. the inlay layout 2)inside the hole 7. The crosslinkable polymer composition 16 may be alsodispensed over the first thermoplastic layer 6 outside the hole in someembodiments. In some embodiments, the crosslinkable polymer composition16 is dispensed into the hole 7. The cross-linkable polymer composition16 may directly contact the electronic components 10 including active orpassive electronic components, e.g., an integrated circuit (IC). Theamount of cross-linkable polymer composition 16 is predetermined andcontrolled. Any extra material exceeding the top surface of firstthermoplastic layer 6 may be removed. In some embodiments, the curableprecursor in the crosslinkable polymer composition 16 is unfilled epoxyor urethane acrylate.

The crosslinkable polymer composition 16 comprises: a curable precursor,which may be selected from the group consisting of acrylate,methacrylate, urethane acrylate, silicone acrylate, epoxy acrylate,methacrylate, silicone, urethane and epoxy. The crosslinkable polymercomposition is a liquid or a paste, and curable under heat or radiation,or both.

A cross-linkable polymer composition 16 formed in accordance with theinvention often comprises a curable precursor, in a liquid or pasteform. Such a curable precursor may be acrylate, methacrylate, urethaneacrylate, silicone acrylate, epoxy acrylate, urethane, epoxy, siliconeor the like. The crosslinkable polymer composition 16 may be unfilled insome embodiments, and comprises filler or other additives in some otherembodiments. The crosslinkable polymer composition 16 may comprise inthe range of about 0.5 wt. % to about 80 wt. % of the filler. The fillercan be inorganic or organic filler. For example, the filler can be aparticulate thermoplastic filler such as polyolefin, polyvinyl chloride(PVC), a copolymer of vinyl chloride and at least another monomer, or apolyester such as polyethylene terephthalate (PET). The at least anothermonomer in the vinyl chloride co-polymer filler may be vinyl ester,vinyl acetate or vinyl ether in some embodiments. The particulatethermoplastic filler may be a compound or a blend comprising athermoplastic resin, for example, a compound or a blend comprising PVC.

The curable precursor in the crosslinkable polymer composition 16 maycomprise a monomer, an oligomer or pre-polymer having functional groups.The precursor may be cross-linkable under a regular curing conditionsincluding but not limited to heating, radiation such as ultraviolet (UV)light, moisture and other suitable conditions including a dual curingmechanism (such as UV plus heat curing). The curable precursor may be inliquid or paste form. Its viscosity may be in the range of 1-100,000cps. In some embodiments, the curable precursor is urethane acrylate.These curable precursors are readily available from specialty chemicalsuppliers. Examples of these suppliers include but are not limited toDymax Corporation of Torrington, Conn. and Sartomer USA, LLC of Exton,Pa. The curable precursor may be epoxy, which provides flexible orflexiblized epoxy after cured.

In some embodiments, a particulate thermoplastic filler may be used.Examples of a thermoplastic filler include, but are not limited topolyolefin, PVC, polyester, copolymer, terpolymer and the like. Apowdered polymer that provides adequate results may be a compound or ablend comprising PVC, or a modified PVC. The particulate thermoplasticfiller can be a copolymer of vinyl chloride and at least anothermonomer, which may be vinyl ester, vinyl acetate or vinyl ether.Examples of such a copolymer are available from Dow Chemical Companyunder trade name of UCAR′, and from BASF of Ludwigshafen, Germany undertrade name of Laroflex™. UCAR™ is a copolymer of vinyl chloride andvinyl acetate. The grades include YYNS-3, VYHH and VYHD. Laroflex™ is acopolymer of vinyl chloride and vinyl isobutyl ether. The grades includeMP25, MP 35, MP45 and MP60. All of these polymer resins are oftensupplied in the form of fine powder. Particulate thermoplastic fillermight be obtained through suspension or emulsion polymerization of oneor more corresponding monomers or, through pulverization of solidplastics. The particulate form can be of any size, by way of example andnot limitation. The particles may be in the range of 0.5-200 microns. Insome embodiments, the particles are in the range of 1-1000 nm.

Cross-linkable polymer composition 16 may further comprise at least onecurative based on general principles of polymer chemistry. Such across-linkable polymer composition 16 becomes a solid cross-linkedcomposition 18 after curing. Preferably, such a cross-linked composition18 is more flexible than the first thermoplastic layer 6 in someembodiments. For example, the cross-linkable composition 16 comprises afirst curative for thermal curing and a second curative for radiationcuring. During the curing or cross-linking reaction, such across-linkable composition transforms into a solid cross-linked polymercomposition. Such a cross-linked polymer composition 18 is also known inthe art as a “thermosetting” polymer or “thermoset” to distinguish itfrom a thermoplastic polymer. In some embodiments, the cross-linkablepolymer composition is unfilled. In some other embodiment, thecross-linkable polymer composition comprises a range of about 0.5 wt. %to about 80 wt. %, and preferably in the range of about 5 wt. % to about50 wt. %, of a filler.

Examples of a suitable crosslinkable polymer composition 16 include butare not limited to a formulation comprising a curable precursor such asacrylate or urethane acrylate. Examples of such a formulation includebut are not limited to X-685-31-1 and X-685-31-2, available from DymaxCorporation of Torrington, Conn. X-685-31-1 is a formulation comprisingisobornyl acrylate, 2-hydroxyethyl methacrylate,2-hydroxy-3-phenoxypropyl acrylate, t-butyl perbenzoate and aphotoinitiator. Its viscosity is 1047 cP. X-685-31-2 is also aformulation comprising isobornyl acrylate, 2-hydroxyethyl methacrylate,2-hydroxy-3-phenoxypropyl acrylate, t-butyl perbenzoate and aphotoinitiator. Its viscosity is 1025 cP. These formulations weredispensed over the inlay layer, and then cured at a raised temperatureof less than 150° C. under a pressure of less than 2 MPa. The resultingcore layer and resulting information carrying cards were successfullymade. These examples are only intended to illustrate embodiments inaccordance with the invention, and as such should not be construed asimposing limitations upon the claims.

Cross-linkable polymer composition 16, which is packed in a syringe, canbe dispensed using the standard dispensing apparatus or equipment foradhesives, encapsulants, sealants and potting compounds. The amount tocross-linkable composition 16 to be dispensed can be calculated andcontrolled based on the volume of the hole 7 and the inlay layer 8. Thedispensing can be performed by a robot.

Referring to FIG. 13, at step 25, the crosslinkable polymer composition16 is degased in a vacuum chamber after being dispensed over the firstthermoplastic layer 6. The degassing process through vacuum can be donewithout any cover sheet over the structure of FIG. 16 in someembodiments. At step 25, a vacuum is applied onto the crosslinkablepolymer composition 16 in a vacuum chamber. The pressure range is in therange of 10 Pa to 1000 Pa. The vacuum can be maintained for 0.5 to 10minutes, preferably 1-3 minutes. The vacuum is released in the end of acycle. One or multiple cycles can be used to achieve a bubble freesample. Such a vacuum process is performed at low temperature,preferably at room temperature.

Optionally, at step 26, as illustrated in FIG. 17, a second release film42 or a second thermoplastic layer 43 is disposed over the structure ofFIG. 16 before the vacuum process. The second release film may be thesame as the first release film as described. The second thermoplasticlayer 43 comprises a thermoplastic material selected from polyvinylchloride, copolymer of vinyl chloride, polyolefin, polycarbonate,polyester, polyamide, and acrylonitrile butadiene styrene copolymer(ABS). The second thermoplastic layer 43 might be the same as the firstthermoplastic layer 6. Its thickness may be in the range of 0.025 mm to0.25 mm. This thermoplastic layer 43 becomes a part of the core layer ifused. Examples of a polyolefin based film may be TESLIN® product,available from PPG Industries.

At step 28, the crosslinkable polymer composition 16 can be cured toform a crosslinked polymer composition 18. The curing step may beperformed under a pressure using radiation or at a raised temperature,or both radiation and heat. Such a pressure may be equal to or less than2 MPa, and the raised temperature might be equal to or less than 150° C.This curing process can be achieved under pressure through a thermalcuring method only. In some other embodiments, curing can be performedthrough a radiation curing mechanism (e.g., UV curing) only.

The inlay layout 2 or the layer structure 40 illustrated in FIG. 17 canbe disposed into a mold for curing. Referring to FIG. 18, an exemplarymold plate for either a bottom plate 15 or a top plate 17 isillustrated. One of the bottom plate 15 and the top plate 17 may be flatin some embodiments. The exemplary plate 15 in FIG. 18 comprises anoutside shim 44 and an inside shim 46 on the base plate of mold plate15. Both outside shim 44 and inside shim 46 may be a tape adhered ontomold plate 15. Such a tape may be high temperature resistant plastictape such as a polyimide tape having an adhesive on one side. In someembodiments, the thickness of the outside shim 44 is greater than thethickness of the inside shim 46. Both shims form a “pocket” inside themold, where the inlay layout 2 or the layer structure 40 illustrated inFIG. 17 is disposed.

FIG. 19 illustrates an exemplary molding set-up. The bottom mold platecomprises shim 44 and shim 46. Shim 46 is thinner than shim 44. Bothshims are polyimide tapes. The top mold 17 is flat without a tape inthis exemplary set-up. The layer structure 40 comprising inlay layout 2illustrated in FIG. 17 is disposed inside the mold. At an exemplary step38, the layered structure 40 is heated under pressure. A suitabletemperature would be one that is sufficiently high to partially or fullycure the cross-linkable polymer composition 16, or hot laminating firstthermoplastic film 6, or both. After the heat treatment, thecross-linkable polymer composition 16 forms a solid. Such a cross-linkedpolymer composition 18 has good adhesion with first thermoplastic layer6 and inlay layer 8 including electronic component 10 and supportingfilm 12. In some embodiments, such a cross-linked composition is moreflexible than first thermoplastic film 6. In some embodiments, thetemperature is in the range of 65-232° C. In some embodiments, thetemperature is less than 150° C.

Both shims described herein are for illustration only. Both shims may bea permanent portion of the mold plates in some other embodiments. Inlaylayer 8 in self-centering inlay layout 2 centers itself during thevacuum step 25 and the initial process of the curing step 26. Asdescribed herein, inlay layer 8 moves or oscillates relative to theedges of hole 7 and internal edges of the first thermoplastic layer 6.During step 25, air bubbles trapped inside the crosslinkable composition16 even under inlay layer 8 may easily escape from composition 16.During the initial process of curing, when composition 16 is warmed up,inlay layer 8 can center itself relative to the edges of hole 7 and thefirst thermoplastic layer 6. When composition 16 is crosslinked andbecomes solid crosslinked composition 18, inlay layer may be fixed afterself-centered. The at least one inlay layer 8 remains self-centeringduring processing and becomes self-centered after the curing step,horizontally and/or vertically relative to the edges of the hole 7, thefirst thermoplastic layer 6, or both.

Process 20 may further comprise cooling the layer structure and peelingoff the first, second, third and fourth release films. Process 20 mayfurther comprise a step of curing the cross-linkable polymer composition16 using visible light, UV or other radiation curing. It may alsocomprise a step of curing via the introduction of moisture or thepromotion of other chemical reactions. After process 20, thecross-linkable polymer composition 16 is cured so as to yield a solid.After the release films are peeled away, a core layer for an informationcarrying card is formed. The core layer comprises a first thermoplasticlayer 6, an inlay layer 8 and a cross-linked polymer composition 18. Thecrosslinkable polymer composition 16 becomes into the crosslinkedpolymer composition 18 in solid state. Different reference numerals areused for the purpose of differentiation only even though they may sharethe same chemical composition. The exemplary core layer 80 for aninformation carrying card from process 20 is illustrate in FIG. 20.

Referring to FIG. 80, an exemplary core layer 80 of an information carrycard, is fabricated according to the structure depicted FIGS. 1-3, 16-17and steps of FIGS. 13 and 14. More particularly, the exemplar core layer80 comprises a first thermoplastic layer 6, an inlay layer 8, and across-linked polymer composition 18. First thermoplastic layer 6 ispolyvinyl chloride (PVC), a copolymer of vinyl chloride, polyolefin,polycarbonate, polyester, polyamide, acrylonitrile butadiene styrenecopolymer (ABS), or the like. Cross-linked polymer composition 18 isformed from a cross-linkable composition 16 as described in relatedsections above. Inlay layer 8 comprises electronic components 10, forexample, at least one printed circuit board (PCB), supporting film 12and interconnects 14. The electronic components, such as a battery andan active or passive electronic components 10, are connected withinterconnects 14. Electronic components 10 are embedded on supportingfilm 14. The cross-linked polymer composition 18 fills the voids andremaining spaces inside the hole on first thermoplastic layer 6 andinlay layer 8. In some embodiments, the cross-linked polymer composition18 directly contacts the outer surface of electronic components 10.Inlay layer 8 may have any dimension relative to the size of a hole inthe first thermoplastic layer 6. Inlay layer 8 may be partially or fullydisposed into such a hole.

As shown in FIG. 20, in some embodiments, the crosslinked polymercomposition 18 from the crosslinkable polymer composition 16 is disposedabove the first thermoplastic layer 6 outside the hole 7, for example,in the range of 1 micron to 100 micron in thickness.

In some embodiments, the first thermoplastic layer 6 defines a pluralityof holes 7 therein (or therethrough), the inlay layout 2 comprises aplurality of inlay layers 8 coupled with the first thermoplastic layer6, and each inlay layer 8 is disposed inside a respective one of theplurality of holes 7. The resulting core layer 80 is for making aplurality of information carrying cards simultaneously.

The present disclosure provides the resulting products, including a corelayer. In some embodiments, a core layer 80 for at least one informationcarrying card comprises at least one thermoplastic layer 6 defining atleast one hole 7 therein (or therethrough), an inlay layout 2 comprisingat least one inlay layer 8 coupled (e.g., flexibly coupled) with thefirst thermoplastic layer 6, and a crosslinked polymer composition 18disposed over the inlay layout 2 and contacting the inlay layer 8. Eachinlay layer is at least partially disposed inside a respective hole. Asdescribed above, the first thermoplastic layer 6 comprises athermoplastic material, which may be selected from the group consistingof polyvinyl chloride, copolymer of vinyl chloride, polyolefin,polycarbonate, polyester, polyamide, and acrylonitrile butadiene styrenecopolymer (ABS). The at least one inlay layer 8 is coupled with thefirst thermoplastic layer 6 so as to form a cantilevered structurewithin a respective hole 7, and is configured to be self-centered in thecrosslinked polymer composition 16. The at least one inlay layercomprises at least one electronic component, wherein the at least oneelectronic component 10 is partially or fully disposed inside therespective hole 7. The at least one electronic component 10 in the inlaylayer 8 may comprise at least one integrated circuit, at least one lightemitting diode (LED) component, or a battery. The inlay layout 2 or thecore layer 80 may comprise at least one of a metal sheet (such asstainless steel), a ceramic sheet, a wooden sheet, and carbon fiberbased sheet. The crosslinked polymer composition 18 comprises a baseunit selected from the group consisting of acrylate, methacrylate,urethane acrylate, ester acrylate, silicone acrylate, epoxy acrylate,silicone, urethane and epoxy. The base unit in the crosslinked polymercomposition 18 comprises urethane acrylate or epoxy in some embodiments.The first thermoplastic layer 6 defines a plurality of holes 7 therein.The inlay layout 2 may comprise a plurality of inlay layers 8 coupledwith the first thermoplastic layer 6, each inlay layer is disposedinside a respective hole 7 of the plurality of holes, and the core layer80 is configured to be used for making a plurality of informationcarrying cards.

3. Information Carrying Card

In some embodiments, the invention also provides a method forfabricating an information carrying card. The method comprises forming acore layer as described above. Such a method for making informationcarrying card may comprise laminating a printable thermoplastic film onone side of the core layer. A printable thermoplastic film may belaminated on each side of the core layer. Such a method may furthercomprise laminating a transparent thermoplastic film on the printablethermoplastic film on one side of the core layer. A transparentthermoplastic film may be laminated on the printable thermoplastic filmon each side of the core layer.

In some embodiments, an information carrying card comprises a core layeras described above. In some embodiments, the information carrying cardfurther comprises at least one printable thermoplastic film laminatedonto the surface of the core layer. The information carrying cardfurther comprises at least one transparent film laminated onto thesurface of the printable thermoplastic film in some embodiments. Theinformation carrying card further comprises at least one batteryinterconnected with the at least one electronic component in the inlaylayer in some embodiments. The information carrying card may alsocomprise at least one sheet of metal, ceramic, metal containingmaterial, ceramic containing material, wood, carbon fiber basedmaterial, plastics or the like.

Referring to FIGS. 21-26, exemplary process 150 of making an exemplaryinformation carrying card includes the following steps as shown in FIG.26. The layer structure at different steps of an exemplary process 150is shown in FIGS. 21-25. Referring to FIG. 21, a transparent film 132 isprovided first. A transparent film 132 can be used as the outer layer ofan information carrying card. Examples of transparent film 132 includebut are not limited to PVC and PET. In step 152 of FIG. 26, referring tothe structure shown in FIG. 22, a printable thermoplastic film layer 134is disposed onto the transparent film 132. The printable thermoplasticfilm 134 is an imaging receiving layer. Words or images can be printedonto the printable thermoplastic film 134 before or during a process ofmaking an information card. In some embodiments, this film is nottransparent, and contains some pigments such as white pigments.

In step 154 of FIG. 26, a core layer 80 is disposed onto the printablethermoplastic layer 134 and the transparent film 132. One resultingexemplary layer structure is shown in FIG. 23. Referring again to FIG.20, in some embodiments, an exemplary core layer 80 comprises a firstthermoplastic layer 6, an inlay layer 8, and a cross-linked polymercomposition 18. Inlay layer 8 comprises electronic components 10, forexample, at least one printed circuit board (PCB), supporting film 12and interconnects 14. The electronic components, such as a battery andan active or passive electronic components 10, are connected withinterconnects 14. Electronic components 10 are embedded orsurface-mounted on supporting film 12. Cross-linked polymer composition16 fills the voids and remaining spaces inside the hole on firstthermoplastic layer 6 and inlay layer 8. In some embodiments,cross-linked polymer composition 18 directly contacts the outer surfaceof electronic components 10.

In step 156 (FIG. 26), a second printable thermoplastic layer 134 isdisposed onto the layered structure of FIG. 23, followed by a secondtransparent film 132. The exemplary resulting layer structures are shownin FIG. 34 and FIG. 25. In some embodiments, at least one release filmis used on each side of the layer structure of FIG. 25. Examples of therelease film include a sheet of polytetrafluoroethylene, any otherfluoropolymer, silicone, a fluoropolymer or silicone coated films. Insome embodiments, a breathable release film is used.

In step 158 (FIG. 26), the exemplary layer structure after step 156 islaminated under a pressure at a raised temperature. The layeredstructure after step 156 is pressed under a pressure. In someembodiments, the pressure is less than 2 MPa. The layered sandwichstructure is then is heated at a raised temperature under the pressure.A suitable temperature is sufficiently high so that all the films arelaminated with good adhesion. In some embodiments, the temperature is inthe range of 65-232° C. In some embodiments, the temperature is lessthan 150° C. The information carrying card may have different sizes. Insome embodiments, the information card may have a size following ISO/IEC7810 standard. For example, an ID-1 type smart card, which is for mostof the banking card and ID cards, has a size of 85.6×53.98 mm.

In some embodiments, the exemplary process 150 comprises a process suchas surface treatment to improve adhesion between two layers. Examples ofsurface treatment methods include but are not limited to plasmatreatment or corona treatment before hot lamination at step 158.

The exemplary processes 20 and 150 can be used to make a plurality ofinformation carrying cards on one sheet simultaneously, in accordancewith some embodiments. An exemplary core layer structure 80 comprising aplurality of inlay layer 8 can be fabricated using process as describedabove. Cross-linked polymer composition 18 fills the voids and remainingspaces inside the hole on first thermoplastic layer 6 and inlay layer 8.In some embodiments, cross-linked polymer composition 18 directlycontacts the outer surface of electronic components 10. Referring againto FIG. 13, a crosslinkable polymer composition 16 is disposed over theinlay layer inside each hole to form the crosslinked polymer composition18. An exemplary crosslinkable composition comprises a curable precursorwith or without fillers. The curable precursor is urethane acrylate,ester acrylate, silicone acrylate, epoxy acrylate, acrylates includingmethacrylate, silicone, urethane, epoxy or the like. The crosslinkablecomposition 16 is cured to form a crosslinked composition 18. Examplesof curing method include but are not limited to thermal and radiationcuring. In some embodiments, thermal curing occurs during a thermallamination process. In some embodiments, the exemplary core layerstructure 80 is further laminated with at least one printablethermoplastic layer and a transparent film. The resulting laminatedstructure is then cut to form a plurality of information carrying cards.In some embodiments, the pressure is preferably less than 2 MPa. Thetemperature is in the range of 65-232° C. in some embodiments, and ispreferably less than 150° C. in some embodiments in the laminationprocess.

Rectangular shaped information carrying cards or smart cards in thisdisclosure are for illustration only. The disclosure structure andprocess of making also apply to any information carrying card or part ofany shapes and any size. Examples of these parts include but are notlimited to rectangular sheets, circular sheets, strips, rods and rings.The size includes but is not limited to any size following ISO/IEC 7810standard.

Although the subject matter has been described in terms of exemplaryembodiments, it is not limited thereto. Rather, the appended claimsshould be construed broadly, to include other variants and embodiments,which may be made by those skilled in the art.

1.-34. (canceled)
 35. A method for forming a core layer for at least oneinformation carrying card, comprising: arranging a portion of at leastone inlay layer with a first thermoplastic layer to provide an inlaylayout, wherein the first thermoplastic layer comprises a thermoplasticmaterial and defines a hole therein, cantilevering the at least oneinlay layer with the first thermoplastic layer so as to be free to moverelative to a the hole; and dispensing a crosslinkable polymercomposition over the inlay layout and contacting the inlay layer so asto form the core layer of the information carrying card, wherein the atleast one inlay layer is configured to be self-centering in thecrosslinkable polymer composition.
 36. The method of claim 35 whereinthe step of forming the inlay layout comprises: providing the firstthermoplastic layer defining the at least one hole therein; forming acantilever projection on an edge of the at least one inlay layer so asto couple the at least one inlay layer and the first thermoplastic layerso that the at least one inlay layer is free to move relative to thehole.
 37. The method of claim 35 further comprising: disposing the firstthermoplastic layer over a first release film.
 38. The method of claim35 further comprising disposing a second thermoplastic layer or a secondrelease film above the inlay layout after dispensing the crosslinkablepolymer composition.
 39. The method of claim 38 wherein the first orsecond thermoplastic layer comprises a thermoplastic material selectedfrom the group consisting of polyvinyl chloride, copolymer of vinylchloride, polyolefin, polycarbonate, polyester, polyamide, andacrylonitrile butadiene styrene copolymer (ABS).
 40. The method of claim35, wherein the crosslinkable polymer composition comprises: a curableprecursor, the curable precursor selected from the group consisting ofacrylate, methacrylate, urethane acrylate, silicone acrylate, epoxyacrylate, methacrylate, silicone, urethane and epoxy, and thecrosslinkable polymer composition is a liquid or a paste.
 41. The methodof claim 35 wherein the at least one inlay layer comprises at least oneelectronic component, wherein the at least one electronic component ispartially or fully disposed inside the respective hole.
 42. The methodof claim 41 wherein the at least one electronic component in the inlaylayer comprises at least one integrated circuit.
 43. The method of claim41 wherein the at least one electronic component in the inlay layercomprises at least one light emitting diode (LED) component or abattery.
 44. The method of claim 35 wherein the inlay layout comprises ametal sheet.
 45. A method for fabricating at least one informationcarrying card, comprising forming a core layer according to claim 35.46. The method of claim 45 further comprising laminating a printablethermoplastic film on one side of the core layer.
 47. A method of claim46 wherein a metal sheet is laminated on at least one side of each corelayer.
 48. A core layer for at least one information carrying cardcomprising: at least one thermoplastic layer defining at least one holetherein; the first thermoplastic layer comprising a thermoplasticmaterial; an inlay layout comprising an inlay layer cantilevered to aportion of a first thermoplastic layer so that the inlay layer is freeto move within the at least one hole; and a crosslinked polymercomposition disposed over the inlay layout and contacting the inlaylayer.
 49. The core layer of claim 48 wherein the thermoplastic materialis selected from the group consisting of polyvinyl chloride, copolymerof vinyl chloride, polyolefin, polycarbonate, polyester, polyamide, andacrylonitrile butadiene styrene copolymer (ABS).
 50. The core layer ofclaim 48 wherein the at least one inlay layer is is configured to movefreely so as to be self-centered in the crosslinked polymer composition.51. The core layer of claim 48 wherein the at least one inlay layercomprises at least one electronic component, wherein the at least oneelectronic component is partially or fully disposed inside therespective hole.
 52. The core layer of claim 51 wherein the at least oneelectronic component comprises at least one integrated circuit.
 53. Thecore layer of claim 51 wherein the at least one electronic componentcomprises at least one light emitting diode (LED) component or abattery.
 54. The core layer of claim 48 comprising a metal sheet.